Negative pressure wound therapy barrier

ABSTRACT

A barrier for use in negative pressure wound therapy can include a base layer and surface structures. The barrier can be used to reduce or prevent tissue ingrowth. A method of using a negative pressure wound therapy system can include positioning a perforated barrier in a wound. After positioning the perforated barrier in the wound, positioning a pad in the wound on top of the perforated barrier, positioning a seal on top of the wound to at least partially seal the perforated barrier and the foam in the wound, and applying negative pressure wound therapy to the wound.

TECHNICAL FIELD

The present invention relates to patient wound care, and morespecifically to systems and methods of wound coverings and dressings.

BACKGROUND

Negative-pressure wound therapy (NPWT) is a type of treatment used byphysicians to promote the healing of acute or chronic wounds. Forexample, sealed wound dressings connected to a vacuum pump can be placedonto an open wound for applying sub-atmospheric pressure to the wound.Such types of negative-pressure applications can be used to draw outfluid from the wound and increase blood flow to a wound area.

SUMMARY

Some embodiments include methods and systems for use in negativepressure wound therapy (NPWT). A barrier can be configured to bepositioned adjacent to wound tissue and prevent or reduce tissueingrowth from the wound tissue into a pad positioned above the barrier.The barrier can have structures configured to allow for fluid flow yetstill inhibit tissue ingrowth. The barrier can be provided separatelyfrom existing NPWT dressings and/or used with the existing NPWT dressingto improve performance. The barrier can include irrigation flow channelsto allow for simultaneous irrigation and NPWT. The barrier can includeone or more other features described herein.

In some implementations, a method of using a negative pressure woundtherapy system includes providing or receiving a wound dressingcomprising a pad and a membrane, wherein the pad is porous, wherein thepad and the membrane are configured to be used for negative pressurewound therapy, providing or receiving a barrier, wherein the barrier isprovided separately from the wound dressing, wherein the barrierincludes a plurality of perforations, wherein the barrier is configuredto be positioned in a wound adjacent to wound tissue, and wherein thebarrier is configured to prevent or reduce tissue ingrowth from thewound tissue into the pad, and positioning the barrier in the woundadjacent to the wound tissue. After positioning the barrier in thewound, the pad can be positioned in the wound on top of the barrier in alocation that is spaced from the wound tissue by the barrier, the sealcan be positioned on top of the pad and wound to at least partially sealthe barrier and the pad in the wound, and negative pressure woundtherapy can be applied to the wound while the pad and the barrier arepositioned in the wound such that fluid is allowed to flow from thewound tissue, through the perforations of the barrier, through the poresof the pad, and through an outlet of the wound dressing.

Implementations can include any, all, or none of the following features.The pad may be an open cell foam sponge, wherein the barrier is aninjection molded polymer barrier having complex geometry that isconfigured to space the open cell foam sponge material from the woundtissue to reduce or prevent tissue ingrowth. The barrier comprises abase layer and a plurality of walls extending from the base layer,wherein a first plurality of the perforations are positioned so as toextend through the base layer at positions between the walls, andwherein a second plurality of perforations are positioned so as toextend through the base layer at positions under the walls. The wallsform a repeating polygonal shape, wherein the walls meet at wallintersections, and wherein the second plurality of perforations arepositioned under the walls at some but not all of the wallintersections. The walls have a greater height at locations where thewalls connect to the base layer than at locations which have the secondplurality of perforations positioned under the walls. The barriercomprises a base layer and a plurality of walls extending from the baselayer, wherein the walls form a repeating polygonal shape, and whereinposts extend from the base layer at indentations defined between thewalls. The barrier comprises a base layer and a plurality of wallsextending from top and bottom sides of the base layer, wherein thebarrier comprises a plurality of tabs extending from the top side of thebase layer, wherein the tabs are configured to be grabbed to pull thebarrier out of the wound. The method can further include sucking liquidand exudate through the perforations of the barrier, removing the wounddressing, including removing the pad and the membrane, from the wound,and after removing the wound dressing, removing the barrier from thewound by grabbing one or more tabs extending from the barrier with atool or one's fingers and pulling. The barrier comprises an injectionmolded polymer, a radiopaque marker positioned in the injection moldedpolymer, and a coating positioned on an outer surface of the polymer.The pad is an open cell foam sponge, wherein the barrier is a polymerbarrier having complex geometry that is configured to space the woundtissue from the perforations of the barrier, wherein the barrier isintegrally formed as a single piece. The barrier is designed to be usedwith the wound dressing and wherein the wound dressing is designed to beused without the barrier. The barrier has a width that is multiplecentimeters long, wherein the barrier has a length that is multiplecentimeters long, wherein the barrier has a thickness that is 1 to 5 mmthick, and wherein the perforations extending through the barrier have a1 to 5 mm diameter. The plurality of perforations extend through a baselayer of the barrier and wherein the barrier defines structure at leastpartially blocking the perforations. The method can further includecutting the pad to a pad size suitable to be placed in the wound andcutting the barrier to a barrier size suitable to be placed in thewound, wherein the pad and the barrier are cut separately in separatesteps.

In some implementations, a method of using a negative pressure woundtherapy system includes positioning a perforated barrier in a wound.After positioning the perforated barrier in the wound, positioning a padin the wound on top of the perforated barrier, positioning a seal on topof the wound to at least partially seal the perforated barrier and thepad in the wound, and applying negative pressure wound therapy to thewound.

In some implementations, a barrier for use in negative pressure woundtherapy includes a base layer and top surface structures. The base layerdefines a plurality of perforations through the base layer, wherein theplurality of perforations are positioned, sized, and configured to allowflow therethrough for negative pressure wound therapy, wherein the baselayer defines a top surface and a bottom surface. The top surfacestructures are positioned on the top surface of the base layer, whereinthe top surface structures are positioned, sized, and configured tospace porous foam material away from the perforations of the base layerwhen porous foam material is positioned on top of the barrier after thebarrier is positioned in the wound.

Implementations can include any, all, or none of the following features.The barrier has a thickness and a structure configured to create aphysical separation between the pad and reduce or prevent tissueingrowth through the perforations to a porous foam material positionedabove the barrier. The top surface structures comprise walls forming arepeating geometric shape, and wherein the walls at least partiallycover and block at least some of the perforations through the baselayer. The top surface structure comprises walls forming a repeatinggeometric shape, posts positioned between the walls, and tabs extendingupward from the walls. The base layer and the top surface structurescomprise a pliable medical grade polymer and further comprisingfilaments or radiopaque markers embedded in the pliable medical gradepolymer. The barrier defines a first set of irrigation channels and asecond set of irrigation channels, wherein a plurality of irrigationchannels from the second set of irrigation channels branch out from eachof the irrigation channels in the first set of irrigation channels. Thebarrier defines an inlet along an edge of the barrier, wherein the inletis fluidly connected to the first set of irrigation channels and thesecond set of irrigation channels with the first set of irrigationchannels positioned between the inlet and the second set of irrigationchannels. This inlet can extend normal to the surface of the barrier, topass through and overlying pad and connect to an irrigation source. Thebarrier defines an inlet at a middle portion of the barrier, wherein theinlet is fluidly connected to the first set of irrigation channels andthe second set of irrigation channels with the first set of irrigationchannels positioned between the inlet and the second set of irrigationchannels.

In some implementations, a negative pressure wound therapy systemincludes a wound dressing comprising a membrane, a pad comprising aporous foam sponge configured to be positioned under the membrane, and abarrier configured to be positioned under the pad. The barrier includesa plurality of perforations, wherein the pad and the barrier areconfigured to be positioned together in a wound with the barrierpositioned adjacent to wound tissue and the pad positioned between thebarrier and the membrane, and wherein the barrier is configured toprevent or reduce tissue ingrowth from the wound tissue into the pad.

Implementations can include any, all, or none of the following features.The pad is an open cell foam sponge, wherein the barrier is an injectionmolded or otherwise fabricated polymer barrier having complex geometrythat is configured to space the open cell foam sponge material from thewound tissue to prevent tissue ingrowth. The barrier comprises a baselayer and a plurality of walls extending from the base layer, wherein afirst plurality of the perforations are positioned so as to extendthrough the base layer at positions between the walls, and wherein asecond plurality of perforations are positioned so as to extend throughthe base layer at positions under the walls. The barrier comprises abase layer and a plurality of walls extending from the base layer,wherein the walls form a repeating polygonal shape, and wherein postsextend from the base layer at indentations defined between the walls.The barrier comprises an injection molded polymer, a radiopaque markerpositioned in the injection molded polymer, and a coating positioned onan outer surface of the polymer. The plurality of perforations extendthrough a base layer of the barrier and the barrier defines structure atleast partially blocking the perforations. The barrier is physicallyattached to the pad so as to be sold and delivered together. The barrieris attachable to the pad via one or more fasteners. The barrier definesa first set of irrigation channels and a second set of irrigationchannels, wherein a plurality of irrigation channels from the second setof irrigation channels branch out from each of the irrigation channelsin the first set of irrigation channels.

In some implementations, a barrier for use in negative pressure woundtherapy and wound irrigation includes a base layer defining a pluralityof perforations through the base layer, wherein the plurality ofperforations are positioned, sized, and configured to allow flowtherethrough for negative pressure wound therapy, wherein the base layerdefines a top surface and a bottom surface. The barrier defines a firstset of irrigation channels and a second set of irrigation channels,wherein a plurality of irrigation channels from the second set ofirrigation channels branch out from each of the irrigation channels inthe first set of irrigation channels. The perforations of the barrierare sized, positioned, and configured to allow for suction flow from awound surface positioned under the bottom surface of the base layer,through the perforations, and to an area above the top surface of thebase layer. The first and second sets of irrigation channels of thebarrier are sized, positioned, and configured to allow for irrigationthrough the first and second sets of irrigation channels to the woundsurface. The barrier is configured to allow for the suction and theirrigation simultaneously.

Implementations can include any, all, or none of the following features.The barrier defines an inlet along an edge of the barrier, wherein theinlet is fluidly connected to the first set of irrigation channels andthe second set of irrigation channels with the first set of irrigationchannels positioned between the inlet and the second set of irrigationchannels. The barrier defines an additional irrigation channel extendingfrom the inlet to the second set of irrigation channels so as to fluidlyconnect the inlet to the first set of irrigation channels. The barrierdefines an inlet at a middle portion of the barrier, wherein the inletis fluidly connected to the first set of irrigation channels and thesecond set of irrigation channels with the first set of irrigationchannels positioned between the inlet and the second set of irrigationchannels. The inlet tube is of sufficient length to more than traversethe full thickness of the pad overlying the barrier, whether the pad isplaced piece-meal as a separate unit during dressing application or ismanufactured to be fixedly attached to the barrier as a single unit. Theinlet tube will also penetrate the sealing membrane after completeapplication of the dressing and then connect to an irrigation supplytubing which communicates the irrigant from the irrigation source to thedressing. The point at which the inlet tube will penetrate or cross thesealing membrane can be further improved, by including an integratedflat manifold, which acts to hold the inlet tubing, generally normal tothe dressing in a central location, and further provide a flat surfacewhere the sealing membrane can be adhered at application of the dressingto the body. This flat surface allows for easier application of thesealing membrane encouraging an airtight seal for the dressing, which isa preferred state. This manifold can also include a separate attachmentpoint or coupling for the suction tubing that extends from the regulatedvacuum source to the dressing. The barrier further comprises top surfacestructures positioned on the top surface of the base layer, wherein thetop surface structures are positioned, sized, and configured to spaceporous foam material away from the perforations of the base layer whenporous foam material is positioned on top of the barrier after thebarrier is positioned in the wound. The second set of irrigationchannels terminate at outlets that are positioned at the bottom surfaceof the barrier, wherein some of the outlets are positioned proximate aperimeter of the barrier with other outlets positioned closer to acenter of the barrier. A tubular extension extends from the inlet in adirection that is generally normal to the barrier. A system includes thebarrier, a wound dressing comprising a pad with the barrier fixedlyattached to the pad, and a tubular extension that extends from theirrigation inlet of the barrier through the pad to an end that isconfigured to be connected to an irrigation source. The tubularextension is configured to allow for simultaneous irrigation andnegative pressure. The tubular extension is configured to allow foralternating irrigation and negative pressure. A manifold is fluidicallyconnected to the tubular extension. The manifold is positioned adjacentthe pad at a location where the tubular extension extends through thepad. The manifold defines a suction inlet configured to connect tosuction tubing.

In some implementations, a system includes a wound dressing comprising amembrane, a pad, and a barrier. The pad comprises a porous foam spongeconfigured to be positioned under the membrane. The pad comprises a padbottom, a pad top, and pad sides. The barrier is wrapped around the pad,wherein the barrier is configured to prevent or reduce tissue ingrowthfrom the wound tissue into the pad.

Implementations can include any, all, or none of the following features.The barrier is wrapped around a pad bottom and at least part of the padsides. The barrier is wrapped around a circumference of the pad. Thebarrier is wrapped completely around a circumference of the pad. Thebarrier and the pad are sized and shaped to be used in fistulous ortunneled wounds that have a long narrow geometry. The pad comprises asponge. The barrier comprised medical grade polymer The barrier definesperforations. The pad and barrier combine to form a shape that is longand narrow at a distal end and wider and flatter at a proximal end. Thebarrier is substantially nail shaped. The barrier is substantiallyfunnel shaped. The barrier is substantially kettle shaped. The barriercomprises a head portion and a cylinder portion The cylinder portion isperforated. The cylinder portion is wrapped around the pad sides. Thewound dressing comprises one or more irrigation flow paths configured todeliver irrigant to the barrier. The wound dressing comprised one ormore suction flow paths configured to provide negative pressure at thedressing. The one or more irrigation flow paths are independent from theone or more suction flow paths. A method of using the wound dressingincludes cutting a distal end of the wound dressing so as to cut boththe pad and the barrier. The pad can be moved at least partially out ofthe distal end of the wound dressing. A portion of the pad that waspulled out of the distal end of the wound dressing can be cut. The padcan be moved back into the wound dressing. The pad can be positionedinside the barrier such that the pad is spaced inward from a distalopening of the barrier by a gap. A distal opening of the barrier can beclosed after the barrier has been cut. A distal opening of the barriercan be sutured after the barrier has been cut.

Other features, aspects and potential advantages will be apparent fromthe accompanying description and figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a negative pressure wound therapy system(NPWT) and a patient.

FIG. 2 is a schematic view of a negative pressure wound therapy system.

FIG. 3 is a perspective view of a barrier for use in the negativepressure wound therapy system of FIG. 2.

FIG. 4 is a top view of the barrier of FIG. 3.

FIG. 5 is an enlarged perspective view of a portion of the barrier ofFIG. 3.

FIG. 6 is a top view of a barrier having irrigation channels.

FIGS. 7A and 7B are top and side views of another barrier havingirrigation channels.

FIG. 8 is a flow chart for a method of using the negative pressure woundtherapy system of FIG. 1.

FIG. 9A is a perspective view of a barrier and FIG. 9B perspective viewsof a dressing using the barrier of FIG. 9A. Both the barrier and thedressing can be configured for use in providing NPWT relatively deep andnarrow wounds, such as gunshot wounds and/or cutaneous fistulas.

FIGS. 10A-10D show a series of steps for trimming the dressing of FIGS.9A-9B.

FIGS. 11A-11B show a series of steps for suturing the dressing of FIGS.9A-9B.

FIG. 12 shows a barrier for a wound dressing having a nail shape.

FIG. 13 shows a barrier for a wound dressing having a funnel shape.

FIG. 14 shows a barrier for a wound dressing having a kettle shape.

FIG. 15 is a perspective view of a dressing having a combined sponge andbarrier.

FIGS. 16A-16C are views of features of a barrier.

FIG. 17 is a perspective view of a dressing having a combined sponge andbarrier with irrigation tubing.

FIG. 18 is a perspective view dressing having a combined sponge andbarrier with a suction manifold and irrigation tubing.

DETAILED DESCRIPTION

The technology disclosed herein generally relates to a system, deviceand method for negative pressure wound therapy (NPWT). A dressing forNPWT can include a foam sponge pad or wound filler that is placed in thewound and a sealing membrane that covers the wound and the foam spongepad. A hose can connect the dressing to a vacuum source to applyregulated NPWT to the wound to beneficially facilitate healing of thewound. However, current systems can result in undesirable tissueingrowth into pores of the foam sponge pad within 2 to 3 days. Thisingrowth not only limits the potential safe duration of wear, it alsoleads to increased pain and wound tissue trauma when the dressing ischanged. A barrier can be positioned under the foam sponge pad or woundfiller to separate the foam sponge pad away from the wound and toprevent or restrict tissue ingrowth during NPWT. The barrier can be madeof a flexible medical grade polymer material and can have complexgeometry that can allow flow of fluid and exudate through the barrierduring NPWT yet still prevent or restrict the wound tissue from growinginto the foam sponge pad or wound filler. The barrier can be used withexisting wound dressings that are designed for use without such abarrier, or can be part of a wound dressing where the barrier isattached to the foam sponge pad or other type of wound filler (i.e.gauze). In this scenario, during the manufacturing of the sponge orwound filler, a similar barrier construct could be attached to thesponge pad/wound filler in order to substantially prevent ingrowth. Thebarrier could also replace the sponge or wound filler completely.Replacement can be performed at the manufacturing stage by the productmanufacturer or at the application stage by the clinician.

Tissue ingrowth is undesirable because it has several consequences. Whena dressing is removed after tissue ingrowth into the dressing hasoccurred, this can result in the tearing of healthy tissue away from thewound surface. This is particularly problematic when the wound exposescritical or delicate structures, such as blood vessels, nerves orvisceral organs. This phenomenon results in significant pain withdressing changes and traumatizes the wound tissues, which can be adverseto the healing process. For this reason, dressing changes are requiredfrequently to prevent too much ingrowth, usually within 2 or 3 days,therefore a barrier that prevents or reduces in-growth could allow forextended duration of wear which is a unique clinical benefit of someaspects of this invention. Tissue ingrowth can also result in tearing ofthe sponge or wound filler resulting in foreign matter being left behindin the wound. These areas of foreign matter can create inflammatoryresponses, heterotopic ossification and/or infections.

FIG. 1 shows a schematic view of a negative pressure wound therapy(NPWT) system 100 and a patient 102 having a wound (not shown in FIG.1). The NPWT system 100 includes an electronic vacuum regulator (EVR)104, a canister 106, a tubing system 108, and a wound dressing 110. NPWTcan occur in a hospital setting or outside of the hospital with chronicwounds.

The EVR 104 can include a controller (including one or more processorsand memory) and a flow rate meter having one or more valves and sensorsto measure and control the flow rate of liquid through the EVR 104and/or the amount of negative pressure applied. In some embodiments, theEVR 104 can include a pump or other device configured to producenegative pressure. In some embodiments, the EVR 104 can be connected toa pump or other device configured to produce negative pressure, such asa wall vacuum source or a dedicated vacuum source.

The wound dressing 110 can be configured to cover and substantially seala wound of the patient 102. The tubing system 108 can include one ormore hoses to connect the wound dressing 110, the canister 106, and theEVR 104 to apply negative pressure (a vacuum) to the wound of thepatient 102. The canister 106 can collect liquid removed from the woundof the patient 102.

In some embodiments, the NWPT system 100 can be configured differentlythan as illustrated. For example, one or more of the EVR 104, thecanister 106, the tubing system 108, and the wound dressing 110 can beshaped and positioned differently than as illustrated. Additionally, oneor more components can be added, replaced, or removed from the NWPTsystem 100. For example, the canister 106 can be replaced with acollection bag.

FIG. 2 is a schematic view of the NWPT system 100, including the EVR104, the tubing system 108, and the wound dressing 110 (the canister 106is omitted from FIG. 2).

A portion of the patient 102 is shown including a wound 112. In theillustrated example, the wound 112 is a relatively deep wound into theflesh of the patient 102. The wound 112 can be deep enough to extendthrough skin tissue 122, through fat tissue 124, and into muscle tissueor visceral spaces 126 of the patient 102. In other examples, the wound112 can be deeper or less deep depending on the injury to the patient102.

In the illustrated embodiment, the wound dressing 110 includes a tubingconnector 114, a membrane 116, and a pad 118, such as a foam sponge pad,a gauze pad, or other type of wound filler. The pad 118 can be an opencell foam pad (commonly called a sponge) that is cut to size and placedin the wound 112. The membrane 116 can be a relatively thin membraneconfigured to substantially seal the wound 112. The tubing connector 114can connect to the tubing system and extend through the membrane 116 toallow for the EVR 104 to apply negative pressure to the wound 112. Thepad 118 can be porous to allow flow of liquid and gas between the tubingconnector 114 and a surface of the wound 112. The membrane 116 can havean adhesive positioned around a perimeter of the membrane 116 that isconfigured to stick the membrane 116 to the patient 102 and seal thewound 112 well enough that the EVR 104 can suitably apply negativepressure to the wound 112 to promote new tissue growth.

In some embodiments, an additional barrier 120 can be added under thepad 118. The barrier 120 can be a separation layer that is positionedbetween the pad 118 and the surface of the wound 112 to space the pad118 from the surface of the wound 112 and prevent or reduce tissuein-growth into pores of the pad 118.

In some embodiments, the tubing connector 114, the membrane 116, and thepad 118 can be part of a wound dressing 110 for a negative pressurewound therapy system that is intended to be delivered without thebarrier 120 and is configured for use without the barrier 120. In suchsituations, the wound dressing 110 can be intended to be used with thepad 118 placed into the wound 112 and covered by the membrane 116without placing the barrier 120 under the pad 118. In such situations,NPWT can be performed without the barrier 120, however, doing so canallow for tissue ingrowth into pores of the pad 118. Therefore, thebarrier 120 can be provided separately as an additional structure toimprove upon an existing wound dressing 110 where the pad 118 is aporous foam material that is susceptible to tissue ingrowth.

The barrier can also be placed to provide protection from desiccation ordrying out of susceptible structures such as tendons, nerves, bloodvessels, and/or bone. The barrier can be coated with a lubricant such asVaseline or even antimicrobials such as antibiotics, silver compounds orother materials such as growth factors or other chemicals or medicationsto promote tissue healing and/or prevent infection.

The barrier 120 can be added as an additional structure in order toprevent or reduce in-growth of tissue (e.g. the muscle tissue orvisceral organs 126) into pores of the pad 118. The barrier 120 canspace the pad 118 from one or more tissues in order prevent or reducecontact with those tissues. In the illustrated embodiment, the barrier120 is positioned under the pad 118 and also wrapped at least partiallyaround sides of the pad 118 to space the pad 118 from tissue. In theillustrated embodiment, the barrier 120 is positioned between the pad118 and the muscle tissue 126, but not necessarily between the pad 118and the fat tissue 124 (the barrier 120 is shown adjacent to only partof the fat tissue 124) or the skin tissue 122. Such a configuration canbe used where it is desired to prevent ingrowth from the muscle tissue126 while ingrowth by the fat tissue 124 and the skin tissue 122 isdeemed to be less of a concern. In other embodiments, the barrier 120can be larger or smaller and placed to cover more (e.g. covering all orpart of each of the skin tissue 122, the fat tissue 124, and/or themuscle tissue 126) or fewer tissues as suitable for the application.

In other embodiments, not illustrated herein, the barrier 120 can bewrapped fully or partially around the pad 118, thereby fully orpartially enclosing the pad 118. This particular embodiment would bemost useful for deep tracts or tunnels in the wound, in which woundfiller is often placed to apply NPWT and prevent loculation. Thesespecific embodiments can have preferred shapes (i.e. cylindrical orrectangular) and dimensions for commonly treated deep wound tracts ortunnels. The advantage of these embodiments over traditional methods, isthat the barrier can serve its innovative function of physicallyseparating the wound filler from the wound tissue to prevent or reduceingrowth in a more circumferential fashion in parts of the wound thathave more than just a single planar surface that needs to heal.

As explained above, the barrier 120 can be a structure that is entirelyseparate from the pad 118, and it can be sold and provided separatelyfor use with a version of the wound dressing 110 that was intended to beused without the barrier 120. In alternative embodiments, the barrier120 can be attached to the pad 118 and can be sold and deliveredtogether (see, for example, the dressings 610, 710, and 810 describedbelow with respect to FIGS. 15-18). In further alternative embodiments,the barrier 120 can be provided separately from the pad 118, yet beconfigured to be attached to the pad 118 such as by using one or morefasteners at the time of application of the dressing.

The barrier 120 is a porous barrier configured to reduce or preventtissue ingrowth. In some embodiments, the barrier 120 can be shaped andconfigured as illustrated in FIGS. 3-5. In other embodiments, thebarrier 120 can have different shapes and features as suitable for theapplication. Multiple layers of different geometric shapes such ascircles, hexagons, polygons, screens, etc. can be used to createpathways for suction transmission and fluid or gas passage while stillcreating a barrier between the solid but compressible sponge or woundfiller and the wound. These layers can be separate or manufactured as asingle unit. Perforations in the barrier can allow flow both paralleland perpendicular to the surface of the wound to improve or optimizeNPWT functionality.

Current sponges or other wound fillers are open cell structures thatallow for pieces or parts of the sponge to be left behind in the wound.Likewise, when gauze is used as a wound filler, it can become unraveledalso resulting in pieces being left in the wound. The barrier can becreated to reduce this by ensuring a closed cell structure. A barrierthat is devoid of surface pores that are in the 400-600 micron range forexample, can prevent or reduce in-growth into the dressing. Avoidingforeign material being left inside the wound is optimal.

FIG. 3 is a perspective view of the barrier 120. FIG. 4 is a top planview of the barrier 120. FIG. 5 is an enlarged perspective view of aportion of the barrier 120. The barrier 120 can include complex geometryconfigured to space tissue away from a porous pad 118 to reduce orprevent tissue ingrowth. Therefore, the barrier 120 provides a physicalseparation between the wound and the in-growth inducing surface of thewound filler. For example, the barrier 120 can include a base layer 130and structure extending from the base layer 130, such as walls 132 andposts 134.

The walls 132 can define a repeating polygonal shape, such as therepeating hexagonal shape illustrated in FIG. 3. In other embodiments,the walls 132 can define a different repeating polygonal shape than asillustrated. In other embodiments, the walls 132 can define a differentnon-polygonal repeating shape, such as repeating circles. In otherembodiments, the walls 132 can define different shapes as suitable forthe application.

The walls 132 and the posts 134 can extend substantially normally fromthe base layer 130 to impart thickness to the barrier 120. The posts 134can be positioned substantially centrally in one, more than one, or allof spaces (or indentations) defined by the walls 132. The posts 134 canprovide an offset to help keep tissue (i.e. the muscle tissue 126) ormaterial (i.e. material of the pad 118) out of the spaces defined by thewalls 132. In other embodiments, the posts 134 can be omitted if thebarrier is shaped and configured to suitably operate without the posts134.

The base layer 130 of the barrier 120 can define a plurality ofperforations (or pores) 136 extending through the base layer 130. Thebase layer 130 can define one or more perforations 136 extending throughthe base layer 130 in each of the spaces defined by the walls 132 andcan define perforations 136 extending through the base layer 130 atpositions under the walls 132. In some embodiments, the perforations 136are the only passages extending entirely through the base layer 130.

As shown in FIG. 4, the base layer 130 includes three perforations 136in each of the hexagonal spaces (or indentations) defined between thewalls 132. In other embodiments, more or fewer than three perforations136 can be positioned in each of the spaces defined between the walls132.

As shown in FIG. 4, the base layer 130 also includes one perforation 136extending through the base layer 130 at some of the intersections of thewalls 132. As shown, the base layer 130 includes perforations 136 underroughly half of the intersections of the walls 132. In otherembodiments, the base layer 130 can include more or fewer perforations136 positioned under the walls 132 than as illustrated.

As best illustrated in FIG. 5, the walls 132 can have a smaller heightat portions 132A of the walls 132 that are positioned over perforations136 and can have a taller height at portions 132B of the walls 132 thatare connected to the base layer 130. This can allow for increased flowthrough perforations 136 that are positioned under the walls 132. Thisdifferent in wall height also forms passages through the walls 132 thatcan facilitate flow laterally across the barrier 120.

In some embodiments, the barrier 120 can include one or more tabs 138extending away from the base layer 130. The tabs 138 can be sized,shaped, and configured to allow for a user (e.g. a doctor or othermedical provider) to pull on the tabs 138 to remove the barrier 120 fromthe wound 112. The tabs 138 can have a strength that is suitable towithstand the force of pulling on the tabs 138 without tearing after thebarrier 120 has been left in the wound 112 for an extended period (e.g.several hours or several days). Additional embodiments include suture orwire that can extend outside the barrier 120 to enable or facilitateremoval.

In some embodiments, the base layer 130 can be the bottom-most layer ofthe barrier 120 and be configured for a bottom surface 142 of the baselayer 130 to be positioned adjacent the surface of the wound 112. Thestructure extending up from a top surface 140 of the base layer (e.g.the walls 132 and the posts 134) can be positioned adjacent the porousmaterial of the pad 118. In such embodiments, the barrier 120 can spacethe pad 118 away from the wound 112 so as to prevent or reduce tissueingrowth into the pad 118 without additional structure extending from abottom side of the base layer 130. In some embodiments, the barrier 120can be manufactured as an integral component of the sponge pad or woundfiller 118, such that the two elements are not separate, but one. Such acomposite improved NPWT dressing could possess most commonly anopen-cell foam sponge superficial surface (i.e. facing away from thewound), whose primary purpose would be to facilitate transmission ofnegative pressure to the wound and evacuation of wound fluids from thewound 112 surface. Then a barrier layer can be fixedly attached on awound-facing surface of this composite dressing. Such a barrier layercan serve the same purpose as the barrier 120 does in other embodimentsin which the barrier 120 is an independent and separate piece. Such abarrier would be a physical barrier intended to prevent or reduce tissuein-growth into the open-cell foam sponge or other wound filler material.In this way, this embodiment would not be an add on to current NPWTdressings, but rather a uniquely new NPWT dressing with enhancedcapability over and above the current art.

In other embodiments, the barrier 120 can have structure extending fromboth of the top and bottom surfaces 140 and 142 of the base layer 130.For example, the barrier 120 can have walls 132 and posts 134 extendingfrom the bottom surface 142 that are substantially a mirror image to thewalls 132 and the posts 134 extending from the top surface 140 (exceptthat the tabs 138 can be omitted). Alternatively, the barrier 120 canhave structure extending from the bottom surface 142 of the base layer130 that is different than the structure extending from the top surface140 of the base layer 130. Structure that extends from the top surface140 can be sized, shaped, and configured to interface with the pad 118.Structure that extends from the bottom surface 142 can be sized, shaped,and configured to interface with the muscle tissue 126 or some othertissue of the patient 102 to prevent or resist the muscle tissue 126from clogging the pores 136 when the muscle tissue 126 grows during thenegative pressure wound therapy.

As shown in FIG. 4, the walls 132 can at least partially block at leastsome of the perforations 136 when viewed from the top (see, e.g., FIG.4). In some embodiments, the barrier 120 includes structure (e.g. thewalls 132) that at least partially block all of the perforations 136that extend through the base layer 130. In such embodiments, all (orsubstantially all) of the perforations 136 are at least partiallyblocked to prevent or reduce tissue growth from extending through thebarrier 120 to pores of the pad 118.

The barrier 120 can be a one piece structure with complex geometry.Accordingly, the base layer 130, the walls 132, the posts 134, and thetabs 136 can be integrally formed as a single construct. Alternativedesigns can allow for the barrier 120 to have multiple layers and allowfor removal of some layers to decrease the height of the barrier by thetreating provider at the time of dressing application. The barrier 120can be integrally formed by injection molding via a pliable medicalgrade polymer. For example, the barrier 120 can be made of silicon orpolyurethane. In other embodiments, the barrier 120 can be made ofpolydioxanone, or another material that is able to dissolve if leftimplanted in the patient 102 for many days.

The barrier 120 can be constructed of biodegradable material and left inthe wound 112 permanently. The barrier 120 can be clear, colored, ortinted to allow for easy identification within the wound 112 in order toprevent it from being left in the wound 112, for versions of the barrier120 that are not biodegradable. A radiographic marker can be included inthe barrier 120 to allow for identification by radiograph, as a means ofpreventing unintended retention of a dressing in a wound.

In some embodiments, the barrier 120 can be made of a transparent ortranslucent material. This can allow for better visualization of thewound 112 under the barrier 120. The barrier 120 can also be tinted(such as tinted purple, green, and/or blue) to increase visibility inthe wound 112 so as to avoid or reduce the risk of the barrier 120 beingundesirably left in the wound 112. In some embodiments, the barrier 120can be both tinted as well as transparent or translucent. In someembodiments, the tabs 138 (or other removal handles) can be colored andsome or all of other portions of the barrier 120 can be clear and notcolored.

In some embodiments, the barrier 120 can be formed of a material and canbe sized and shaped to be both somewhat pliable and somewhatshape-retaining. For example, the barrier 120 can be pliable enough tobend to conform to a shape of a wound and/or to wrap at least partiallyaround a sponge or other pad 118, such as shown schematically in FIG. 2.Additionally, the barrier 120 can be rigid enough such that thestructure (e.g. the walls 132 and posts 134) at least partially retainits shape when placed in the wound 112 under the pad 118 and negativepressure is applied to allow for flow through the barrier 120.

In some embodiments, the barrier 120 can be configured to be cut.Doctors or other medical personnel can cut the barrier 120 to shape soas to fit in the wound 112 depending on the shape of the wound 112. Insome of such embodiments, the barrier 120 can also be rigid enough to beheld in one hand and cut with the other hand without the barrier 120sagging undesirably limp during the cutting process.

The barrier 120 can be sized to be relatively long and wide as viewedfrom the top (see FIG. 4) and to have a relatively thin thickness (orheight) as viewed on-edge. For example, the barrier 120 can have alength and width that are each several centimeters long and a thicknessthat is about 1 to 5 mm thick. In embodiments where the barrier 120includes the tabs 138, the barrier 120 can have a thickness of 1 to 5 mmnot including the tabs 138 such that the tabs 138 effectively increasethe thickness of the barrier 120 to more than 1 to 5 mm.

The barrier 120 can have a relatively high tensile strength so as toresist ripping when in tension.

The perforations 136 can be sized large enough to allow for flow throughthe barrier 120 such that the NPWT system 100 functions effectively toapply negative pressure to the wound 112 below the barrier 120. Forexample, the perforations 136 can each have a diameter of about 1 to 5mm. The perforations 136 of the barrier 120 can be sized and shaped toallow for the sucking of liquid and exudate through the perforations 136without clogging the perforations 136 (or with reduced clogging of theperforations 136).

The walls 132 and/or the posts 134 can have a thickness (when viewedfrom the top as in FIG. 4) that is small enough to allow the barrier 120to be flexible and that is large enough to at least partially resistcompression when the barrier 120 is placed under the pad 118 andnegative pressure is applied. For example, the walls 132 and/or theposts 134 can have a thickness (when viewed from the top as in FIG. 4)of between 1 and 5 mm.

In some embodiments, the barrier 120 can include radiopaque material.Radiopaque material can help ensure that the barrier 120 is visibleduring x-ray imaging, which, can allow medical professionals to removethe barrier 120 from the patient 102 in the event that the barrier 120is accidentally left inside the patent after the barrier 120 wassupposed to be removed. For example, the barrier 120 can include one ormore radiopaque markers such as thin diameter wires (not shown) embeddedwithin flexible, medical-grade polymer material that forms the barrier120. In some embodiments, a radiopaque thin diameter wire can bepositioned in the barrier 120 at the one or more tabs 138 to bothreinforce the tabs 138 and to help confirm removal using radiography.The wire or suture can also be used as “rebar” to reinforce the tensilestrength of the barrier 120 and resist tearing. The wire or suture inthis embodiment would typically be manufactured to lay within the wallsof the barrier 120.

In some embodiments, the barrier 120 can include a coating. For example,the barrier 120 can be coated with a lubricant. Coating with a lubricantcan be beneficial in situations, such as, when used in wounds withexposed bone or tendon to help prevent (or resist) the bone or tendonfrom drying out. Alternatively or in addition, the barrier 120 can becoated with a bacteriostatic agent that is configured to stop or slowthe reproduction of bacteria. Alternatively or in addition, the barrier120 can be coated with an antibiotic coating. Moreover, the barrier 120can be coated with another coating that is deemed suitable for theapplication.

In some embodiments, the barrier 120 can include irrigation flowchannels (e.g. see the irrigation channels of FIGS. 6, 7A, and 7B)extending through the barrier 120. For example, irrigation flow channelscan extend through the barrier 120 along a main trunk line flowingthrough a middle portion of the barrier 120 and with branch linesextending out from the trunk line. Accordingly, such a barrier 120 canallow for irrigation to be supplied to the wound 112 through the flowchannels and be suctioned away from the wound 112 through theperforations 136 of the barrier 120 and through the pores of the foam ofthe pad 118. This type of dressing can support either simultaneous oralternating periods of irrigation and suction. If alternating betweensuction and irrigation, there can be periods of dwell time betweenperiods spent irrigating or suctioning the wound. If and when trimmingof the barrier 120 is desired for the barrier 120 having irrigation flowchannels, the barrier 120 could be trimmed in areas where there arebranch lines while maintaining the inlet to the trunk line untrimmed. Inembodiments that do not require irrigation, the barrier 120 need notinclude flow channels.

FIG. 6 is a top view of a barrier 150 having irrigation channels 152,154, and 156. The irrigation channel 152 can be a main trunk line fromwhich the irrigation channels 154 branch off. The irrigation channels156 can, in turn, branch off the irrigation channels 154. Accordingly,the irrigation channels 152, 154, and 156 can be oriented similar to theveins in a leaf where a central tube (e.g. the irrigation channel 152)branches into additional tubes (e.g. the irrigation channels 154 and/or156) to cover the entire surface. This orientation can allow a tube 158to enter from a side of the barrier 150 to supply irrigant to thebarrier 150. In other embodiments, the tube can be positionedsubstantially normal and central to the non-wound facing surface of thebarrier and the irrigation channels can extend radially from this tube.This tube can be long enough to extend through or more than through thecommon thickness of a wound filler, like foam sponge. In someembodiments, a clamp 160 can be included on the tube 158 to clamp downand seal or restrict flow through the tube 158. In some embodiments, thetube 158 can include a connector 162 for connecting to additional tubing(e.g. to the tubing system 108 described above with respect to FIGS. 1and 2). In some embodiments, the barrier 150 can be substantiallysimilar to the barrier 120 described above except for the addition ofthe irrigation channels 152, 154, and 156. In such embodiments, thebarrier 150 can be used to supply irrigant to the wound (via theirrigation channels 152, 154, and 156), and simultaneously allow fornegative pressure wound therapy, with liquid and exudate sucked throughthe perforations 136 (not shown in FIG. 6). By allowing for negativepressure wound therapy simultaneously with irrigation, this can reduceor eliminate the need for a dwell time between irrigation and negativepressure wound therapy. In various embodiments, the barrier 150 can haveone or more different structures as suitable for the application as abarrier having irrigation channels.

FIGS. 7A and 7B are top and side views of a barrier 170 havingirrigation channels 172 and 174. The irrigation channels 172 formmultiple main trunk lines from which the irrigation channels 174 branchoff. A tube 176 connects to the barrier 170 at a middle portion 178, andthe irrigation channels 172 extend radially outward from the middleportion 178. Accordingly, this alternate orientation of the barrier 170would allow for the tube 176 to be run outside of the barrier 170 (aboveit) and allow radial tubes (the irrigation channels 172) to be designedto take the irrigation towards a periphery of the barrier 170. Theirrigation channels 174 can terminate at outlets 180 that are positionedon a bottom surface of the barrier 170 and/or at the periphery of thebarrier 170. Some of the outlets 180 can be positioned proximate aperimeter of the barrier 170 so as to irrigate tissue near the perimeterof the barrier 170 and some of the outlets 180 can be positioned closerto a center of the barrier 170 so as to irrigate tissue near the centerof the barrier 170. In alternative embodiments, the barrier 170 can haveirrigation channels that are different than those illustrated.

The barriers 150 and 170 can have features (e.g. walls 132, posts 134,and/or perforations 136) and uses that are the same or similar to thosedescribed herein for the barrier 120. For example, one of the barriers150 or 170 can be used in a manner similar to the barrier 120 asdescribed above for FIG. 2, with the barrier 150 or 170 added as anadditional structure in order to prevent or reduce in-growth of tissue(e.g. the muscle tissue or visceral organs 126) into pores of the pad118. The barrier 150 or 170 can be a structure that is entirely separatefrom the pad 118, and it can be sold and provided separately for usewith a version of the wound dressing 110 that was intended to be usedwithout the barrier 150 or 170. In alternative embodiments, the barrier150 or 170 can be attached to the pad 118 and can be sold and deliveredtogether (see, for example, the dressings 610, 710, and 810 describedbelow with respect to FIGS. 15-18). In further alternative embodiments,the barrier 150 and 170 can be provided separately from the pad 118, yetbe configured to be attached to the pad 118 such as by using one or morefasteners at the time of application of the dressing.

In some embodiments, the barriers 150 and 170 can be configured to betrimmed (e.g. via scissors) to substantially match the size of the wound112 and still function to supply irrigant to the surface of the wound112. For example for the barrier 150, the tube 158 is attached to thebarrier 150 along one edge. Accordingly, the barrier 150 can be trimmeddown to size by trimming the other three edges while maintaining thestructural integrity of the connection between the tube 158 and thebarrier 150. During trimming, one or more of the channels 154 and 156can be cut and yet the barrier 150 can still function to supply irrigantto the surface of the wound 112 through those portions of the channels154 and 156 that remain.

Additionally, for the barrier 170, the tube 176 is attached to thebarrier 160 at the middle portion 178. Accordingly, the barrier 170 canbe trimmed down to size by trimming any of the four edges whilemaintaining the structural integrity of the connection between the tube176 and the barrier 170 at the middle portion 178. During trimming, oneor more of the channels 172 and 174 can be cut and yet the barrier 170can still function to supply irrigant to the surface of the wound 112through those portions of the channels 172 and 174 that remain.

In some embodiments, the barrier 120 (as well as the barriers 150 and170) can include filaments that act to reinforce the integrity of thebarrier 120 in a manner that is similar to rebar in concrete. Suchfilaments can be in the form of suture material, a metal, a fabric,and/or a stronger polymer. The filaments can be high tensile materialthat helps resist or prevent portions of the barrier 120 beingfragmented and retained in the wound 112.

The filaments can be in a central portion of the barrier 120 in planewith the barrier 120, such that the filaments are in-line to transect orfollow the margins of the perforations 136. The filaments can also be ina random pattern to allow for improved tensile strength without beingtoo bulky. In some embodiments, the filaments can be in the form of amesh layer that is embedded in the barrier 120 prior to the barrier 120being perforated. A perforating tool can cut a hole in the barrier 120,and also in the mesh filaments imbedded in the barrier 120. Thus, themesh filaments can optionally be positioned in order to prevent orreduce overlap across the perforations 136.

These filaments can optionally traverse the perforations 136. If thefilaments do traverse the perforations 136, the filaments can serve as asieve to prevent tissue in-growth yet permit the evacuation of woundfluids.

In alternative embodiments, the barrier 120 can be formed as a flatwoven mesh layer or a three dimensional mesh structure (such as a potscrubber or loofah) dipped or coated in silicone or similar materialthat is bio-compatible/inert. Such a mesh structure could also besimilar to a honeycomb type structure. The mesh structure can offertensile strength and compressibility. The mesh structure can beconstructed of suture, metal, polymer, or fabric material. The meshstructure can form a core material that offers tensile strength and thatis coated to prevent or reduce tissue ingrowth. Constructing the barrier120 in this manner can allow for a compressible structure withsignificant fluid pathways to allow irrigation passage as well astransmit negative pressure. In some embodiments, the barrier 120 canhave a structure that is constructed of transparent coating over thinfilaments (such as a PDS, proline, monocryl, or woven polyester such asethibond, fiberwire, or vycryl). The barrier 120 can be made ofnon-dissolvable or dissolvable material. In another embodiment, thebarrier 120 can include a dissolvable polyglycolate material. In anotherembodiment, the barrier 120 can include collagen based materials tocreate structural support but still allow a fully dissolvable barrier120.

In some embodiments, the barrier 120 can also be used with any suitablesystem as a sponge, pad, or wound filler replacement. By removing thepad 118 (or any other wound filler) and using the barrier 120, theclinician can see the wound 112 assuming the barrier 120 is constructedof a clear material. The tabs 138 can be trimmed to allow for easiersealing over the barrier 120. The barrier 120 can be used with anysuitable system that incorporates a sealing layer 102 and suction tubing108.

FIG. 6 is an example method 200 of using the NPWT system 100. At step202, the wound 112 of the patient 102 is prepared. This can includecleaning the wound 112, removing necrotic tissue, and/or otherprocedures deemed necessary or desirable. At step 204, the wounddressing 110 is provided. The wound dressing 110 can include the tubingconnector 114, the membrane 116, and the pad 118 (such as a sponge orother filling material). The wound dressing 110 can be intended to beused, and can be suitable to be used, without an additional barrier(such as the barrier 120). However, adding the wound dressing 110 can bebeneficially added as described below in steps 208 and 210.

At step 206, the wound dressing 110 is prepared. Components of the wounddressing 110 can be removed from packaging, assembled, and/or trimmed.For example, the pad 118 can be trimmed to a size and shape suitable forbeing positioned in the wound 112 of the patient 102. The wound dressing110 can now ready to be applied to the wound 112, except when it isdeemed desirable to use the barrier 120. If the wound dressing 110 is tobe used without the dressing 112, the method 200 can proceed to step214. If the benefits of the barrier 120 are desired, steps 208, 210, and212 can be performed.

At step 208, the barrier 120 is provided. The barrier 120 can beintended for use with the wound dressing 110 and similar wound dressingsto improve treatment of the patient 102, yet the barrier 120 is providedseparately from the wound dressing 110. At step 210, the barrier 120 isprepared. The barrier 120 can be removed from packaging. In embodimentswhere the barrier 120 is a single, integrally formed barrier, noassembly is needed. The barrier can be trimmed to a size and shapesuitable for being positioned in the wound 112 under the pad 118 toseparate the pores of the pad 118 from some or all of the surface of thewound 112.

At step 212, the barrier 120 can be positioned in the wound. The barrier120 can be positioned to substantially cover all (or substantially all)of the surface of wound tissue. Alternatively, the barrier 120 can bepositioned to cover only a portion of the tissue in the wound, such asthe muscle tissue 126. Covering the muscle tissue 126 can be beneficialbecause the muscle tissue 126 can tend to grow into the pores of spongeymaterial like the pad 118, and consequently, pain and tissue damage canresult when the pad 118 is removed from the wound 112 when such tissueingrowth occurs. Other tissue, such as fatty tissue 124, can be lessprone to ingrowth, and consequently, it can be less important to coversuch fatty tissue 124 in such circumstances. Nonetheless, the fattytissue 124 and other tissue can also be covered by the barrier 120.

At step 214, the wound dressing 110 can be applied. The pad 118 can beplaced in the wound 112 on top of the barrier 120 and the membrane 116can be applied to cover the wound 112. The tubing connector 114 can beapplied so as to connect to tubing for applying NPWT.

At step 216, negative pressure wound therapy (NPWT) can be applied tothe wound 112. The EVR 104 can work in conjunction with a vacuum sourceto apply negative pressure to the wound 112 in order to aid in healing.

When the wound dressing 110 is applied without the barrier 120, thewound dressing 110 can be used for a period of 24-72 hours or less. Evenwhen removed within 24-72 hours or less, tissue ingrowth can occurpotentially causing pain, tissue damage, and breakage of portions of thespongy material of the pad 118 and remaining in the wound 112 when thepad 118 is pulled out of the wound 112.

When the wound dressing 110 is applied with the barrier 120 positionedunder the pad 118, pain, tissue damage, and/or breakage can be reduced.In some applications, the wound dressing 110 and the barrier 120 can beleft in for longer than 24-72 hours because the barrier 120 can inhibittissue ingrowth. Accordingly, use of the barrier 120 can increase theeffective life and duration of each wound dressing 110.

FIGS. 9A-9B show perspective views of a wound dressing 300 for NPWT anda barrier 306 for use in the wound dressing 300. The wound dressing 300can be suitable for use with relatively long (or deep) and narrowwounds, such as gunshot wounds and/or cutaneous fistulas. The wounddressing 300 can include a membrane 302, a pad 304, and the barrier 306.The barrier 306 can be wrapped substantially or entirely around acircumference of the pad 304. An irrigation tube (or lumen) 308 can beused to supply irrigation to the wound dressing 300. A suction tube (orlumen) 310 can be used to apply negative pressure to the wound dressing300.

In some embodiments, components and features of the wound dressing 300can be similar to those described above (e.g. for wound dressing 110)and also have some differences suitable for use in treating relativelylong and narrow wounds. For example, the pad 304 can be a foam pad (e.g.a foam sponge) like that described above for the pad 118, except the pad304 is long and narrow.

Additionally, the barrier 306 can have features similar to barriersdescribed above. For example, some embodiments of the barrier 306 can bea porous barrier (similar to the barrier 120) that provides physicalseparation between the wound and an in-growth inducing surface of thepad 304. In some embodiments, the barrier 306 can include irrigationchannels similar to the barrier 150 or the barrier 170.

As shown in FIG. 9A, the barrier 306 can be substantially nail-shaped,with a relatively broad and flat connection (or head) portion 312 and arelatively long and narrow cylinder (or shaft) portion 314. The barrier306 defines a relatively long and narrow hollow central core 316. Thecylinder portion 314 can be porous to allow fluid flow through thecylinder portion 314 into the central core 316 during NPWT. The cylinderportion 314 can prevent tissue ingrowth into the pad 304 in the centralcore 316. The barrier 306 can be perforated silicone or other suitablematerial. The barrier 306 can have a geometric structure, such as ahoneycomb shaped structure similar to what is shown in FIG. 3.

FIGS. 10A-10D show a series of steps for trimming the dressing 300. Asshown in FIG. 10A, the dressing 300 can be trimmed by cutting throughthe barrier 306, and possibly the pad 304 as well (e.g. trimming with aknife or scissors). The dressing 300 can be manufactured to a size thatis longer than a depth of the wound to be treated, and then be cut to alength that is deemed appropriate for the depth of the wound. As shownin FIG. 10B, the pad 304 can be exposed at a tip of the dressing 300,uncovered by the barrier 306 after being cut. Accordingly, risk oftissue ingrowth can be increased at the tip of the dressing 300 wherethe pad 304 is uncovered by the barrier 306 due to being cut. As shownin FIG. 10C, a portion of the pad 304 can be pulled out of the distalend of the barrier 306 and then cut shorter. As shown in FIG. 10D, thepad 304 can then be pulled back into the barrier 306 by a distancesuitable to prevent or reduce the risk of tissue ingrowth into the pad304. Accordingly, the dressing 300 can include a gap 318 at the distalend of the dressing 300 where the barrier 306 extends further than thepad 304.

FIGS. 11A-11B show steps for closing the dressing 300 after being cut,such as by suturing. As shown in FIG. 11A, a distal end of the barrier306 can have an opening 320 after being cut. In some embodiments, thedressing 300 can be sized and shaped such that the barrier 306 canprevent or reduce the risk of tissue ingrowth into the pad 304 evenwithout the opening 320 being closed. In other embodiments, the dressing300 can benefit from being closed after being cut to size. Accordingly,the opening 320 can be closed, such as by suturing. For example, theopening 320 can be sutured closed via a vessel loop 322. Alternativelythe opening 320 can be closed by a silicone bond or other suitablemechanism.

FIGS. 12-14 show schematic views of barriers for wound dressings havingdifferent shapes. FIG. 12 is a schematic view of the dressing 300 withthe barrier 306 that is substantially shaped like a nail. The barrier306 can have the flat connection (or head) portion 312 and therelatively long and narrow cylinder (or shaft) portion 314. FIG. 13shows a schematic view of a dressing 400 with a barrier 406 that issubstantially shaped like a funnel. The barrier 406 can have aconnection portion 412 that is substantially frustoconical and acylinder portion 414 (similar to the cylinder portion 314) extendingfrom a narrow end of the connection portion 412. FIG. 14 shows aschematic view of a dressing 500 with a barrier 506 that issubstantially shaped like a kettle. The barrier 506 can have aconnection portion 512 that is relatively wide and flat much like theconnection portion 312 of the barrier 306. The barrier 506 can have ashaft portion 514 that is rounded or bulging as compared to the cylinderportion 314 and the cylinder portion 414. Accordingly, FIGS. 12-14 showsome of the various shapes suitable for treating relatively deep wounds.

In some embodiments, the barriers 306, 406, and 506 can be used with apad (e.g. the pad 304 which can be a foam sponge) positioned inside thebarriers 306, 406, and 506. In other embodiments, the barriers 306, 406,and 506 can be used without any pad or similar structure positionedinside the barriers 306, 406, and 506.

FIG. 15 is a perspective view of a dressing 610 having a combined pad618 (such as a sponge) and barrier 620. The barrier 620 can be attachedor attachable to the pad 618. In some embodiments, the pad 618 can havea thickness of 1-20 mm and the barrier can have a thickness of 1-4 mm.The barrier 620 and the pad 618 can have some, all, or none of thefeatures described above with respect to other examples of barriers andpads. For example, the barrier 620 can include perforations 136. In someembodiments, the barrier 620 and the pad 618 can be combined and soldtogether, with the barrier 620 attached to the pad 618. In suchembodiments, the user need not assemble the barrier 620 and the pad 618.The barrier 620 and the pad 618 can be sized to fit in a given wound orcan be configured to be trimmed together to a size suitable for a givenwound (e.g. a user can cut both the barrier 620 and the pad 618 to anappropriate size using scissors while the barrier 620 is attached to thepad 618).

The dressing 610 can include a tubing system 608, a membrane 616, and anadhesive connection layer 624 (e.g. a “lily pad”). The membrane 616 canbe positioned over the combined pad 618 and the barrier 620 to cover andseal the pad 618 and the barrier 620 in a wound. A hole 626 can be cutin the membrane 616 at a location aligned with the pad 618 and theadhesive connection layer 624 can be adhered to the membrane 616 at thehole 626 to connect the tubing system 608 to the hole 626 to providesuction to the dressing 610 and the corresponding wound.

FIGS. 16A-16C are views of features of the barrier 620. FIG. 16A showsthe barrier 620 having the base layer 130 with a plurality ofperforations 136. A plurality of walls 132 can be positioned above(and/or extend from) the base layer 130 to form a honeycomb or othergeometric shape. While FIG. 16A shows the barrier 620 having only twohoneycomb structures, the barrier 620 can include more honeycomb (orother shaped) structures repeating over some, most, or all of the baselayer 130 (see, e.g. FIGS. 3-5). In some embodiments, the barrier 620can have a combined thickness of the base layer 130 and the walls 132 of1-5 mm. FIG. 16B shows a view of the base layer 130 and its perforations136. FIG. 16C shows a view of the walls 132 forming three honeycombstructures.

FIG. 17 is a perspective view of a dressing 710 having a combined pad618 (such as a sponge) and barrier 720 with irrigation tubing 740. Thedressing 710 can be similar to the dressing 610 (shown in FIG. 15)except the dressing 710 includes irrigation tubing 740. An irrigationsupply tube 742 can be connected to an adhesive connection layer 624(e.g. a “lily pad”) that has connections for both the irrigation supplytube 742 and the tubing system 608 (for providing suction). An extensionirrigation tube 744 can extend through the pad 618, connecting theirrigation supply tube 742 to the irrigation tubing 740 in the barrier720. The irrigation tubing 740 in the barrier 720 can extend radiallyoutward to supply irrigant to a perimeter of the barrier 720. Suctionapplied via the tubing system 608 can draw irrigant and exudate from thewound up through the perforations 136, through the pad 618, through theadhesive connection layer 724, and out through the tubing system 608.

FIG. 18 is a perspective view of a dressing 810 having a combined pad618 (such as a sponge) and barrier 720 with a suction manifold 860 andirrigation tubing 740. The dressing 810 can be similar to the dressing610 (shown in FIG. 17) except the dressing 810 includes the suctionmanifold 860. An extension suction tube 862 can connect the suctionmanifold 860 to the tubing system 608. The suction manifold 860 can bepositioned on top of the pad 618 to distribute the suction force over anarea on top of the pad 618. Fluid can flow into the suction manifold 860through a bottom surface of the suction manifold 860 that is either openor substantially open. Fluid can flow out of the suction manifold 860through a hole in the top of the suction manifold 860 where theextension suction tube 862 is connected to the suction manifold 860.

While this specification contains many specific implementation details,these should not be construed as limitations on the scope of thedisclosed technology or of what may be claimed, but rather asdescriptions of features that may be specific to particular embodimentsof particular disclosed technologies. Certain features that aredescribed in this specification in the context of separate embodimentscan also be implemented in combination in a single embodiment in part orin whole. Conversely, various features that are described in the contextof a single embodiment can also be implemented in multiple embodimentsseparately or in any suitable subcombination. Moreover, althoughfeatures may be described herein as acting in certain combinationsand/or initially claimed as such, one or more features from a claimedcombination can in some cases be excised from the combination, and theclaimed combination may be directed to a subcombination or variation ofa subcombination. Similarly, while operations may be described in aparticular order, this should not be understood as requiring that suchoperations be performed in the particular order or in sequential order,or that all operations be performed, to achieve desirable results.Particular embodiments of the subject matter have been described. Otherembodiments are within the scope of the following claims.

A number of embodiments of the inventions have been described.Nevertheless, it will be understood that various modifications can bemade without departing from the spirit and scope of the invention. Forexample, in some embodiments various components such as radiopaquematerial, filaments, flow passages, etc. need not be included. Moreover,the shape of various features of the barrier can be modified asappropriate. Accordingly, other embodiments are within the scope of thefollowing claims.

What is claimed is:
 1. A method of using a negative pressure woundtherapy system, the method comprising: providing or receiving a wounddressing comprising a pad and a membrane, wherein the pad is porous,wherein the pad and the membrane are configured to be used for negativepressure wound therapy; providing or receiving a barrier configured tobe positioned in a wound adjacent to wound tissue, wherein: the barriercomprises: a base portion defining a plurality of perforations, whereinthe plurality of perforations comprises a first subset of perforationsand a second subset of perforations, and a structural portion adjacentto the base portion and having a plurality of walls defining a pluralityof compartments, wherein: each compartment included in the plurality ofcompartments encloses two or more perforations included in the secondsubset of perforations within a corresponding region of the baseportion, and the plurality of walls form a repeating polygonal shape andmeet at wall intersections, the first subset of perforations arepositioned so as to extend through the base portion at areascorresponding to the wall intersections, the second subset ofperforations are positioned so as to extend through the base portion atareas defined by the plurality of walls, and areas of the plurality ofwalls corresponding to the wall intersections overlying the first subsetof perforations each include a recess extending away from the baseportion, and the barrier is configured to prevent or reduce tissueingrowth from the wound tissue into the pad; positioning the barrier inthe wound adjacent to the wound tissue; after positioning the barrier inthe wound: positioning the pad in the wound on top of the barrier in alocation that is spaced from the wound tissue by the barrier;positioning a seal on top of the wound to at least partially seal thebarrier and the pad in the wound; and applying negative pressure woundtherapy to the wound while the pad and the barrier are positioned in thewound such that fluid is allowed to flow from the wound tissue, throughthe perforations of the barrier, through pores of the pad, and throughan outlet of the wound dressing.
 2. The method of claim 1, wherein thepad is an open cell foam sponge, wherein the barrier is an injectionmolded polymer barrier having complex geometry that is configured tospace the open cell foam sponge material from the wound tissue toprevent tissue ingrowth into the open cell foam sponge material.
 3. Themethod of claim 1, wherein the walls have a greater height at locationswhere the walls connect to the base portion than at locations which havethe second plurality of perforations positioned under the walls.
 4. Themethod of claim 1, wherein the barrier comprises a a plurality of postsextending from the base portion at indentations defined between theplurality of walls.
 5. The method of claim 1, wherein the barriercomprises a plurality of tabs extending from a top side of the baselayer portion facing away from the wound tissue, wherein the tabs areconfigured to be grabbed to pull the barrier out of the wound.
 6. Themethod of claim 1, the method further comprising: sucking liquid andexudate through the perforations of the barrier; removing the wounddressing, including removing the pad and the membrane, from the wound;and after removing the wound dressing, removing the barrier from thewound by grabbing one or more tabs extending from the barrier andpulling.
 7. The method of claim 1, wherein the barrier further comprisestabs, wherein the barrier comprises an injection molded polymerintegrally forming the base, the walls and the tabs, radiopaque markerwires positioned in both the walls and the tabs of the injection moldedpolymer to reinforce tensile strength of the barrier, and a coatingpositioned on an outer surface of the polymer.
 8. The method of claim 1,wherein the pad is an open cell foam sponge, wherein the barrier is apolymer barrier having complex geometry that is configured to space thewound tissue from the pores of the open cell foam sponge, wherein thebarrier is integrally formed by injection molding as a single piece withboth the base portion and the structural portion being formed as aunitary piece of pliable medical grade polymer that is both tinted aswell as transparent or translucent.
 9. The method of claim 1, whereinthe barrier is designed to be used with the wound dressing and whereinthe wound dressing is designed to be used without the barrier.
 10. Themethod of claim 1, wherein the barrier has a width that is multiple cmlong, wherein the barrier has a length that is multiple cm long, whereinthe barrier has a thickness that is 1 to 5 mm thick, and wherein theperforations extending through the barrier have a 1 to 5 mm diameter.11. The method of claim 1, wherein the barrier defines structure atleast partially blocking the perforations.
 12. The method of claim 1,the method further comprising: cutting the pad to a pad size suitable tobe placed in the wound; and cutting the barrier to a barrier sizesuitable to be placed in the wound, wherein the pad and the barrier arecut separately in separate steps.
 13. The method of claim 1, wherein:the barrier comprises: a plurality of posts integrally connected to thebase portion, and wherein terminal portions of the plurality of postseach extend away from the wound tissue.
 14. A method of using a negativepressure wound therapy system, the method comprising: positioning abarrier in a wound adjacent to wound tissue, wherein the barriercomprises: a base portion having (i) a first surface configured tocontact the wound tissue and a second surface opposite to the firstsurface configured to face away from the wound tissue when the barrieris positioned in the wound, and (ii) defining a plurality ofperforations, wherein the plurality of perforations comprises a firstsubset of perforations and a second subset of perforations a structuralportion adjacent to the second surface of the base portion and having aplurality of walls defining a plurality of compartments, wherein: theplurality of walls form a repeating polygonal shape and meet at wallintersections, the first subset of perforations are positioned so as toextend through the base portion at areas corresponding to the wallintersections, the second subset of perforations are positioned so as toextend through the base portion at areas defined by the plurality ofwalls, and areas of the plurality of walls corresponding to the wallintersections overlying the first subset of perforations each include arecess extending away from the base portion, a plurality of postsadjacent to the first surface of the base portion, wherein terminalportions of the plurality of posts extend away from the second surfaceof the base portion; after positioning the barrier in the wound:positioning a seal on top of the wound to at least partially seal thebarrier; and applying negative pressure wound therapy to the wound. 15.A barrier for use in negative pressure wound therapy, the barriercomprising: a base portion having (i) a top surface and a bottom surfaceopposite to the top surface (ii) defining a plurality of perforationsthrough the base portion, wherein: the plurality of perforations arepositioned, sized, and configured to allow flow therethrough fornegative pressure wound therapy, and the plurality of perforationscomprises a first subset of perforations and a second subset ofperforations; a structural portion adjacent to the top surface of thebase portion and having a plurality of walls defining a plurality ofcompartments, wherein: each compartment included in the plurality ofcompartments encloses two or more perforations included in the secondsubset of perforations within a corresponding region of the baseportion, the plurality of walls form a repeating polygonal shape andmeet at wall intersections, wherein: the first subset of perforationsare positioned so as to extend through the base portion at areascorresponding to the wall intersections, the second subset ofperforations are positioned so as to extend through the base portion atareas defined by the plurality of walls, and areas of the plurality ofwalls corresponding to the wall intersections overlying the first subsetof perforations each include a recess extending away from the baseportion; a plurality of posts, wherein terminal portions of theplurality of posts extend away from the bottom surface; and a pluralityof tabs integrally connected to the top surface, wherein the pluralityof tabs are configured to be grabbed to permit removal of the barrierfrom a wound after the barrier is positioned in the wound.
 16. Thebarrier of claim 15, wherein the barrier has a thickness and a structureconfigured to prevent tissue ingrowth from passing through theperforations to a porous foam material positioned above the barrier. 17.The barrier of claim 15, wherein the plurality of walls at leastpartially cover and block at least some of the plurality of perforationsthrough the base portion.
 18. The barrier of claim 15, wherein: the baseportion and the structural portion comprise a pliable medical gradepolymer, and the barrier further comprises filaments or radiopaquemarkers embedded in the pliable medical grade polymer.
 19. The barrierof claim 15, wherein the barrier defines a first set of irrigationchannels and a second set of irrigation channels, wherein a plurality ofirrigation channels from the second set of irrigation channels branchout from each of the irrigation channels in the first set of irrigationchannels.
 20. The barrier of claim 19, wherein the barrier defines aninlet along an edge of the barrier, wherein the inlet is fluidlyconnected to the first set of irrigation channels and the second set ofirrigation channels with the first set of irrigation channels positionedbetween the inlet and the second set of irrigation channels.
 21. Thebarrier of claim 19, wherein the barrier defines an inlet at a middleportion of the barrier, wherein the inlet is fluidly connected to thefirst set of irrigation channels and the second set of irrigationchannels with the first set of irrigation channels positioned betweenthe inlet and the second set of irrigation channels.
 22. The barrier ofclaim 15, wherein: the plurality of walls have a first height; each tabincluded in the plurality of tabs is configured to have a second height;and the second height exceeds the first height.
 23. The barrier of claim15, wherein: the base portion and the structural portion are eachcomposed of a transparent or translucent material; and the plurality oftabs are composed of are composed of a color material.
 24. A negativepressure wound therapy system comprising: a wound dressing comprising: amembrane; a pad comprising a porous foam sponge configured to bepositioned under the membrane; and a barrier configured to be positionedunder the pad in a wound adjacent to wound tissue, wherein: the barriercomprises: a base portion having a first surface configured to contactthe wound tissue and a second surface opposite to the first surface andconfigured to face away from the wound tissue when the barrier ispositioned in the wound, and (ii) defining a plurality of perforations,wherein the plurality of perforations comprises a first subset ofperforations and a second subset of perforations, a structural portionadjacent to the second surface and having a plurality of walls defininga plurality of compartments, wherein:  the plurality of walls form arepeating polygonal shape and meet at wall intersections,  the firstsubset of perforations are positioned so as to extend through the baseportion at areas corresponding to the wall intersections,  the secondsubset of perforations are positioned so as to extend through the baseportion at areas defined by the plurality of walls, and  areas of theplurality of walls corresponding to the wall intersections overlying thefirst subset of perforations each include a recess extending away fromthe base portion, a plurality of posts adjacent to the first surface ofthe base portion, wherein terminal portions of the plurality of postsextend away from the second surface, wherein the barrier is configuredto prevent or reduce tissue ingrowth from the wound tissue into the pad;and wherein the pad and the barrier are configured to be positionedtogether in the wound with the pad positioned between the barrier andthe membrane.
 25. The system of claim 24, wherein the pad is an opencell foam sponge, wherein the barrier is an injection moldedpolydioxanone barrier having complex geometry that is configured tospace the open cell foam sponge material from the wound tissue toprevent tissue ingrowth.
 26. The system of claim 24, wherein the baseportion, the structural portion, and the posts of the barrier areintegrally formed via an injection molded polymer as a unitary piece,radiopaque thin diameter wires positioned in the walls of the injectionmolded polymer, and a coating positioned on an outer surface of thepolymer.
 27. The system of claim 24, wherein the barrier defines a firstset of irrigation channels and a second set of irrigation channels,wherein a plurality of irrigation channels from the second set ofirrigation channels branch out from each of the irrigation channels inthe first set of irrigation channels.
 28. The system of claim 24,wherein the barrier is physically attached to the pad so as to be soldand delivered together.